7.3 Powerstroke No Start When Cold

[@rickycollins4633]

We just went over 1million miles on our 2003 E350 van. The engine has never had major work. I put a FICM on it last year. I didn't think you could kill those FICM's but it did it. It has paid for itself more times than we can count. Giving much but never asking for much. This van almost single handedly maintained a living for my family since it was brand new on the lot.

[@delrossiter9235]

😂😅😅oo😅 on 9qu😅

[@davestrong6472]

Nice job, I have a 24v cummins and always amazed at how well the grid heater works. Dave

[@WatchWesWork]

They do work well down to about 20F.

[@motor2of7]

Had some work done on my 1994.5 power stroke, then the next winter it became VERY cold blooded. Wouldn’t start if the temps went below 40F. Started digging around and found that the shop left the wires off the relay. Hooked em back up good to go.

[@erickieffer8440]

Dude, I love the avatar!

[@motor2of7]

Thanks. It’s a stock image but it fits a back story perfectly.

[@stevenpierno9793]

Why do I get this strange feeling that one of these videos will be this truck in the thumbnail, engine torn out. wires hanging. Fuel, and coolant all over the shop floor?

[@HFG]

I'm so envious of your expertise. I know that comes from a lot of hard work but I'd love to have had access to some of the stuff you've worked on so I could have learned. You're a heck of a mechanic.

[@trenton1880]

I had that exact same truck a few years back Red 5 speed 4x4 7.3 XL model regular cab. That poor truck had a hard life plowing snow and ended up rusting to death thing had 368 thousand miles on it before I gave up on her lol.

[@evanmurphy7659]

382k. She pissed oil but she still runs hot.

[@AntonioClaudioMichael]

Glow plugs aren't hard to change in these old 7.3L engines @Watch Wes Work

[@rickycollins4633]

Ahhhh the wonderful sound of the 7.3!!

[@ranchdog7920]

Peg from the channel “zip ties and bias plies” is the Canadian expert on these engines.

[@tomuchcrazyness9320]

RanchDog yes he is, and he is funny as hell

[@WatchWesWork]

I think "expert" is pushing it...

[@johndowe7003]

@@WatchWesWork ha, yep. have you done the pressure regulator spring swap? i just got mine from 86 diesel i have yet to install it, my old FPR has a bb mod in it but eh ill get to it later lol

[@Boot_185]

Love how kids think that's a cold air intake when its actually warmer air doing that the factory set up.

[@7.3powerstroke6]

Yes it's called a "Cold air intake" but yes is inhales warm air. HOWEVER warm or cold, more air makes a HUGE POWER difference regardless of the temp.

[@Boot_185]

@@7.3powerstroke6 Colder the air the more condensed it is there for makes more power. When the intake tube is the same size as factory you dont get any more air in.

[@motor2of7]

Boot 185 true, unless the restriction is elsewhere, which is the case with the factory air box. The inlet to the box was so restrictive you could see the vacuum of the intake suck the sides of the box in under moderate RPMs. Getting rid of the air box allows for a lot more air flow and horsepower. It’s actually a surprising performance improvement.

[@Boot_185]

@@motor2of7 I remove my air box right away because there is the restriction. Then I run it into the grill and put the filter up there so it gets the cold air from outside and not warm air from the ending compartment.

[@motor2of7]

Boot 185 good setup

[@SmallMartingale]

Fellow Illinoisan here. I've heard you mention a few times that the compression fittings on the brake lines are illegal in Illinois. Where does that info come from? I have no doubt that you're right, I've just never seen any laws governing vehicle repairs before. Great video!

[@mauserdave]

Just installed new glow plugs in mine 95 OBS with 130k miles. Broke one off! Real pain in the butt. Still didn't help with cold starts. Replaced the engine oil temp sensor. With apparently the wrong one. Fired right up when below freezing but holy smokes it sounded like it was running on 4 cylinders and idling at 1400 rpm unplugged the new eot sensor and smooth as silk. Older round style connector on mine I see some for sale with a rectangle connector. Put in a Motorcraft sensor today immediately a world of difference. The glow plug system uses the EOT sensor and the Barometric Pressure sensor in the cab to determine the length of time to power up the glow plugs.

[@billramsey8695]

Thank you so much for the valuable information that you put out. I've worked on all kinds of vehicles. I drive a truck for a living, I would never want to be a mechanic for a living. I admire your abilities and knowledge. Thanks again for the video and information. I have two of these magnificent vehicles. 94 7.3 F250. 99 7.3 F350 dually. They intimidate the heck out of me. But I love them so much. LOL you need to live closer to Central Virginia. LOL take care and God bless

[@WatchWesWork]

These engines are pretty simple compared to what they are building today...

[@Jeremy-iv9bc]

On the 6 liter glow plugs, if you pull the valve cover you can get a small heel bar under the plastic pass through and pop them out.

[@RadioWerwolf]

Nice job, as always. And I love those old school engines not choked with too many electronic gizmos...

[@cameron1328]

changing out my battery, terminals, and glow plugs in my 96 7.3 she deserves it and I don't want to be stranded. Ty for the video!

[@johndowe7003]

I run commercial post type batteries way better than those shitty round post type that are always loose

[@littlewingpsc27]

When doing a resistance check on the glow plugs in the vehicle, wouldn't it be more accurate to remove the old glow plug completely and then measure the resistance on it directly? Otherwise your reading is the sum of the path loss from between the multimeter probes which will include any wires, and other losses through the engine block, etc. You will get a more accurate reading if you pull the plugs and just measure them. Great videos.

[@WatchWesWork]

Actually, the best way to test them is with an clamp on amp meter, but most people don't have one, so I used the ohm meter. It would be most accurate to remove them before measuring, but it shouldn't make a huge difference.

[@danmoeser3863]

After 125000 km just change all 8 simple no need to worry 🙏🙏🙏😃😃😃

[@Netherlands031]

Nice fix. It just came to me that it's a good thing you had a frontal collision in your newer truck instead of this one, safety engineering has improved a lot since then.

[@James-fs4rn]

Thanks for another Wes. I don't start well when it gets cold either. 😀

[@WatchWesWork]

None of us do!

[@narmale]

also, FYI to others: like he said, GPR is on a timer, the idiot Wait To Start light doesn't actually show the state of the GPR, so when it goes off, the relay is still on. It will stay on for about 2 mins, you can watch this in the battery charge while its running. it will go from 11v suddenly jump up to full 14v when the 200ish amp draw suddenly lets off. so if your having issue getting it to fire in the cold, let the relay run longer before cranking.

[@MAGWolf]

Compression brass fitting. Scotty Kilmer must have messed with your truck first :P

[@foxbodyguyeightyeight3672]

If you live in the great white north and like me good rule of thumb for 6.0l and 7.3 change them once every two years

[@beckywatt5048]

foxbody guy eighty eight Don't forget the relay !!!

[@petero2693]

Just for your info..2003 Corolla never garaged...zero rust anywhere... san jose ca.. crazy is it not..

[@ayp1938]

7.3 and a 5 speed nice

[@calholli]

On my 2002 7.3.. The solenoid on top of the motor literally broke in half. Replaced that and got half of my glowplugs back online.

[@connorthesledneck1398]

Yeah, I wouldnt trust that brake line for very long.

Those glow plugs are made by BERU Germany. You can read it even In the vid @7:23 :)

[@JlerchTampa]

I love the 7.3, but you will want to consider putting a spare Cam Position Sensor and a 10mm wrench in the glove box for future no starts. :) Also watch out for the Injector Driver Module getting water in it (Located on the driver fender and known to fail) I recently rebuilt 4 dead IDM's and will post a video on lessons learned and the parts needed soon.

[@WatchWesWork]

It came with one. It's like a spare fuse for a 7.3!

[@victormorgan5508]

Yea thats the truth, just put in number 3 ! what happens when water gets in the idm

[@victormorgan5508]

have a 99 7.3 live in texas when temp gets into the 40s my engine will lope when I first start it, my glow plugs are good /

[@jamesmclellan8768]

So I’ve changed my cps my ipr my hpop getting plenty of fuel do you think my idm might have gone bad I have a 99 f-250 7.3 diesel

[@michaelbenoit248]

If ur engine is healthy enough it should start fine without glow plugs above 35 degrees.

[@istvanmeissler2238]

EXCELLENT video. Much thanks friend.

[@taylormckeel7160]

So what if you have OL on the glow plugs? I did it through the harness

[@theodorefreeman3173]

They will not start with 2 of 3 glow plugs bad.

[@galehess6676]

Be careful with non ford glow plugs (I avoid them as I've seen the damage they do, and at least Autolite are known to be very dangerous to the engine, disintegrating inside the cylinder....). On 7.3 diesel...... 16-009 White-Rodgers (Stancor) 586 902 Monster Glow Plug Relay $55.89 IS a WAY better relay!!! Got my bits from dieselorings.com a very good Ford truck site, for diesels, they have everything at fair prices. I put this one in, and new FORD (ONLY, only use Ford glows, if you have autolite brand, get them out asap, they disintegrate over time, leaving bits in your cylinder... not good). I had a bank of 4 autolites I did not know about, fortunately, they all quit on me, so I pulled them.. only 1 had begun to disintegrate, and fortunately oil samples were still ok). Truck was smoking a bit on startup if less than about 50 degrees, or if plugged in and less than 30. Now, unplugged, it pops right off at any temp down to 30 degress, so far, runs super smooth and no smoke. Runs like a new truck!! The one bank had Ford glows, but only 2 good ones, the dangerous autolite bank was not working at all. Also, replace your batteries. My harness was fine apparently, was replaced a while ago on both sides, maybe 1 year on one side and 4 years ago on the other side. In these 7.3 (and in 6.0, etc.), change engine oil often (consider time elapsed and consider heavy duty usage in plowing, towing or dusty conditions, and maybe change at 1 yr/2k in those situations, or 3-5k otherwise. Can go more than a year and more miles, if testing, and if driving it at least twice a month to burn off moisture or whatever) , this will help injector life and save $$$$. A lot of people testing their oil run 5k with light towing and lots of highway miles, up to 7k some of them, so you may be probably pretty safe going to 7k with all reasonable highway miles. Caterpillar does testing for about 10-15 bucks!!! I added up their cost, vs Blackstone, save like 50 bucks I think it was , and the test came back in 2 days, not 2 weeks lols. I run low miles annually, plowing, and towing /loaded 80% of the time. I Test at somewhere over 1k miles and run it another 1k, and then just change it if I think it's been long enough, even if it's still very likely good. Cheers.

[@robertklein9190]

Wes, is this your day job? It seems your always working on your fleet. Your going backwards, vehicles seem to be getting more antiquated by the minute, but it make good videos. BTW that brake line fix must be the same as that 2001 stretch Excursion limo that just blew thru the intersection in upstate NY killing 20 people.

[@WatchWesWork]

Sometimes older is better...

[@garyfeltus9801]

That was a cool video. Thanks for sharing.

[@repalmore]

This is my first time seeing the 7.3 rocker arms. Wholly crap Batman!!! You can see the stamping seam in them and these engines are really reliable. Most gassers have stamped rocker arms but this is the first diesel with them. And such a simple stamping as well. If it works, what the hell. ;o)

[@narmale]

whoah… compression fitting on brake lines?! what were they thinking >

[@Chris-yy7qc]

Not much

[@narmale]

im amazed it held any pressure... seems like I have trouble with water at 60 psi... let alone dot5.1 at 1400..... >

[@adventureoflinkmk2]

They weren't.

[@narmale]

they were from Arkansas I bet

[@rockcrusher4636]

Fuel gauge doesn't work or she is bone.

[@tristanburke2451]

Well I you know I have the same truck pretty much except it to 350 and it's a dually almost 400,000 miles it's my daily driver zf5 manual with four wheel drive I have the same problem I just use a mixture of ether and diesel to start it when it's really cold

[@MrTL117]

Brown and Shape box! I know that from anywhere! I do miss your cnc lathe series but always an interesting and entertaining watch no matter what you’re working on

[@omegalpha28]

I guess I'm lucky but my 97 7.3 has never failed to start even though it hasn't had a working glowplug relay for the last 2 years.

[@isbcornbinder]

I never had any lasting good service luck with the heated bi-metal switch at the back of the block. I carried a can of ether for the first start of each day. the glow-plugs would burn out when the bi-metal switch would jam shut.

[@dansaver8247]

Very interesting. Thank you. Good comments about the batteries and glow plugs.

[@danaitch3880]

The heck with the glow plugs... What's the story on the machining center teaser at the beginning? :-)

[@teekay1785]

can you use the shim washer kit to raise clearance from worn injector to .04 (4 thousandths) while you are there to aide the cold starts like a 2001 7.3? I don't know the year of yours but it looks like earlier model

[@george420]

I wouldn't call those compression fittings a smart idea. So much for the previous remark of former owner.

[@ab.3800]

It might just be me but that coolant resivor looks like one from like 2000s Silverados lol

[@wolgonautomotive4343]

Way I see it is if they failed I am not gonna use the same brand Motorcraft has let itself go over the years and their parts last about as long as Dorman. NGK for me. Japanese Plugs made well.

[@bcbloc02]

On my Mercedes they need the plugs replaced about every 30K miles. My 5.9 will start well below -10F no plugs and no heaters. My 2 cylinder Deere starts to minus 40F thanks to the pony motor. :-) The NTA 420 will go off at about 40F good with good batteries, my 6030 about the same, colder than that they need plugged up. My Mercedes will start down to 10F below that it gets dicey. I would never advise anyone to own a 6.0 or a 6.4 Power stroke. Same goes for a 3116 Cat.

[@WatchWesWork]

I had great luck with my 6.0. I've started in at -25F many times without plugging in the block heater. Cycle the glow plugs a few times and it would fire right up. Agree on the 3116 Cat though. PITA to do the overhead with the fuel rack in the way. Kinda like an old 2 stroke Detroit. No power, parent bore block, like to eat cams. The 3126 wasn't much better with the HUEI system.

[@djberg3483]

Bah Brian, I'm with Wes, I love my 6.0, she can be a bitch when she wants, but all n all, so much more engine than my old 7.3, and the truck around it is 10x and Dodge truck. Don't get me wrong I respect the hell out of a 24v 5.9, but the Dodge around it, I'll pass. Hey Wes, does that zf5 go into reverse, while completely still? Boy I sure don't miss that either.

[@bcbloc02]

@@flashpointrecycling My 3116 comment was geared mostly towards longevity/cost of ownership issues more so than cold weather problems.

[@flashpointrecycling]

@@bcbloc02 - Hi Brian! understood.

[@robertquast9684]

From what I have heard the 6.0 were ok if you didn’t try and hot rod them

[@7.3life]

I've got to get another 7.3, have a idi in the garage that's a project but want another for a daily. This vid makes me want my 96 back.

[@stevenpierno9793]

Why do I get this strange feeling that one of these videos will be this truck in the thumbnail, engine torn out. wires hanging. Fuel, and coolant all over the shop floor?

[@calholli]

That compression fitting is fine as long as you flare the ends.. if not, then yeah-- - that's a death wish. lol

[@stevenpierno9793]

Why do I get this strange feeling that one of these videos will be this truck in the thumbnail, engine torn out. wires hanging. Fuel, and coolant all over the shop floor?

[@jeromeygreen4788]

Glad I'm not the only person actively using doohickey!

[@gwendeurmier7816]

How do we find the link to the none insulation butt connectors ? Thanks Jimmy D

[@RonReyer]

Thank you for the overview. Very helpful for someone new to the 7.3.

[@subjectofgov]

I've never had a glow plugs that loose on mine. I wonder if I'll break them trying to get them out.

[@fordnut4914]

I got same truck you dont even have to plug mine in when it's cold that thing pops off with ease.

[@hodwooker5584]

I had a Chevy with the 6.2 diesel in it. So needless to say I got really good at changing glow plugs!

[@Chris-yy7qc]

You are a lucky guy. All engines I changed the glowplugs on had at least 1 frozen glowplug. Absolut pita to get out...

[@clarencewiles963]

Thumbs up 👍 easy start ✅

[@bluegrallis]

I think my 95 7.3 might need some diagnosing on the glow plug system. It has decided it doesn't want to start if it gets down around freezing. I may have to plug it in, if I need the truck when it gets much below freezing.

[@WatchWesWork]

Ut oh. Yeah they like glow plugs.

[@buns52557]

Nice Video l'm thinking about changing out my glow plugs on my 97 - 7.3 are they pretty much the same as your 95 7.3 ?

[@WatchWesWork]

Should be the same. I'm pretty sure the 6.0 also uses the same glow plug, but those are much more difficult to change.

[@originaldylanbaxter]

I had the same truck! I wrestled with that damn PowerSmoke for YEARS. Every time the temp went below 40F I'd get a hard start and tremendous white smoke clouds. I swapped glow plugs, upgraded the glow plug relay, swapped out the valve cover wiring harnesses, had the injectors rebuilt, converted to e-fuel and prayed to Rudolph but no joy. If I drove into the office on a cold day and parked in the public lot, there was a real chance the truck would not start at teh end of the day without a lot of glow plug and cranking cycles. Soon the transfer case started acting up, requiring repeated service, and my oil pressure light had begun coming on intermittently with engine stalling. I drove that piece of crap straight to the Dodge stealership and bought a used 2500 with a Cummins. It's been smooth sailing ever since.

[@ApolloTheDerg]

I think mine has bad plugs and dying batteries. It slowed down its turning over and didnt start this morning (was like 39 out too), I just plugged in the block heater and went to work in my gasser. Ill give this all a look, thanks!

[@WatchWesWork]

These engines will not start with weak batteries.

[@un-limited7009]

Thanks

[@psavel274]

Compression fittings for brake lines are also illegal here in New York, but that hasn't stopped me from seeing them on numerous customer cars. Not good.

[@WatchWesWork]

I see them all the time.

[@bborkzilla]

I have to remove the injection pump on my tractor to get to one of the glow plugs. So far, knock on wood, they're all good!

[@TommyCullen-VacuumConnisour]

almost at 100 k good luck

[@JoeHynes284]

impress HS kids....Yes! Exactly!

[@gayle4804]

Always informative 👍

[@Rolingmetal]

Connect the battery direly to the sparkplug. No decent spark then its time to replace the plugs.

[@WCGwkf]

Rolingmetal that's your solution to the problem? Diesels don't have sparkplugs.

[@WatchWesWork]

Believe he means the glow plug. That's a reasonable test, but you'd have to remove it first.

[@kevingoodrich5472]

So I've heard you use the saying " It's only temporary, unless it works" I think you should make a shirt for your merch that has that on it. I would buy one in a minute. It's got a real Roadkill feel to it.

[@WatchWesWork]

It's an old saying. I first heard it from the Red Green show.

[@kevingoodrich5472]

@@WatchWesWork still would make a cool shirt. There is a old movie called "Roadie" with Meatloaf in it and his saying in the movie was" Everything will work, if you let it" Always use that one myself. Goes to over thinking and worrying. Haha!! Love the Red Green show by the way, maybe that's why it sounded so cool!

[@jeffreysnyder4994]

This guy knows his stuff 😊

[@WCGwkf]

Is that your cnc? I wish I had way to get rigging done for cheap, there was an old okuma cnc mill for free on craigslist a couple weeks ago. Would have been sweet to check it out

[@WatchWesWork]

Let's just say that when you have a big truck, big things follow you home...

[@tonytinkle1789]

Ford can I by the ford?

[@johndowe7003]

Air temp intake on a diesel isn't that important especially in these older motors

[@WatchWesWork]

These trucks will start with 2 bad glow plugs. More than that and you can forget it in winter.

[@madmodifier]

Where did they move your fuel filter to? I bought a 97 f350 this February with a 7.3 and I had to change these too.

[@WatchWesWork]

It has a Cat spin on filter down on the frame rail.

[@JSchrumm]

And it even runs on no fuel.

[@bohhica1]

Awesome job, again.👍👍

[@alecchamberlain4231]

Beru

[@ollimatik]

Excellent video - thanks! I think I've got this job coming up shortly!

[@beckywatt5048]

Olli Matikainen Make sure you replace the gaskets and harnesses , I've seen several trucks burn to the ground because of that .

[@erniehenshaw4161]

Another Winner.Good Job.

[@jdboy9]

I believe the 7.3 uses eot to determine run time on the plugs. I think it might use a couple other inputs but I'm not 100%.

[@007.3l]

Yes you are exactly right

[@JourneymanRandy]

Are you using synthetic oil? That will help a lot with cold starting. Costs quite a bit more but worth it if it starts better.

[@casepete6707]

I switch to the t6 synthetic because was having trouble with cold starts. Oh I thought it was great so easy to start no even plugged in but then oil cooler started leaking then turbo. Rebuilt turbo rebuilt oil cooler. New up pipes delete egr pedestal. Always just figured truck cold blooded needed new glow plug year after put in new. Turned out thermostat stuck. Back to 15-40 right oil and now starts just as good as light weight wrong oil. Just thining oil or putting thinner in oil like stiction junk might seem like a miracle to injectors as well but really not just running thinner damaging something down hill. Not a diesel guy or mechanic but did turbo and up pipes and coolor myself and glow plugs. Really have no idea what I'm talking about with my 2 years of 7.3 knowledge 🤣 just a uneducated feeling about wrong weight oil maybe in Alaska but not even here in Iowa I feel

[@scottcuster758]

@@casepete6707 w

[@shortstroke8712]

I’m a big fan of your channel and a subscriber. I also subscribe to Andrew camarata’s channel. I understand that you both have different ways of working on stuff. You do mechanical work for the public but he mostly works on his own stuff which I figure he can fix any way he pleases since it is his. Please quit throwing off on him on your channel. I’ve never heard him disapprove of your work. I think you’re a good person but it doesn’t sound like it when you do that. Just my opinion. Keep the good videos coming. I met a couple at the beach last week and told the husband to check out your channel in that his wife and your wife could be twins. Lol. Later!

[@halldorra]

Beru?

[@ronniewalker2881]

excellent

[@Friedrich-Wilhelm-1980]

no all my 6.9s will start down to -30 without hearers and my 7.3 PSD will start down 0 without skipping a beat

[@panthermartin7784]

Ya can you show us a vid of your 6.9L starting at -30 without glow plugs or being plugged in. Id love to see that.

[@brandonruhl4525]

Panther Martin77 LOL RIGHT

[@WeisCarl2000]

Man your coolant is black, oil in coolant which is prob one of your injector cups is cracked.

[@WatchWesWork]

What? I just had the coolant out last week to fix the oil cooler and it was like brand new. Normally a bad injector cup will result in fuel in the coolant.

[@foxbodyguyeightyeight3672]

Oil in coolant means oil cooler not injector cups

[@joseortiz5965]

Awesome

[@eformance]

I see the heater resistor is not in its home :-)

[@WatchWesWork]

That's the least of it's problems...

[@cameronfast4869]

Thank you!

[@jasonsedy]

Yeah buddy 👍

[@Madmax-iy8fi]

Easy start no probs!

[@willwalt6374]

Great vid 👍🏻

[@eformance]

Where is the fuel bowl?

[@WatchWesWork]

It has a Cat spin on filter by the electric pump.

[@stumpy2816]

👍👍

[@victormorgan5508]

Does it have a fuel bowl heater if so, is it still in use or did you take it out ?

[@WatchWesWork]

The fuel bowl has been removed entirely by the previous owner. He mounted the superduty style pump and filter on the side of the frame rail. It's a hack job, but it works fine and I suppose it's a bit more reliable than the old diaphragm pump.

[@victormorgan5508]

@@WatchWesWork Thank you for the reply. I removed the bowl heater originally because it was blowing the no 30 fuse which also goes to the fuel pump. Just wondering because the engine lopes when I start it in cold weather. saw the truck in the video start fine in 30 degree weather.

[@victormorgan5508]

@@WatchWesWork I should clarify Im talking about the heater coil in the fuel bowl with the fuel filter on top of the engine of my 99 super duty.

[@WatchWesWork]

I've started this engine at -15F with no block heater. It will sounds a bit harsh until the oil warm up, but it should fire on all cylinders. It's hard to say what the issue might be. The Powerstroke needs oil pressure, fuel pressure, compression, and proper voltage at the injectors and ECM to run. The number one cause of cold start issues in these engines is the batteries. If the voltage doesn't stay about 9.5 volts while cranking, they usually won't even start because the ECU will not function correctly. The FICM voltage is an issue with the 6.0, but less so on other models, often that results in long crank time and rough running when really cold. After that is issues with the glow plugs. Usually they will start with 2 bad plugs. 3 or more will not start. Normally fuel issues will be seen under acceleration, not at start up, unless you are getting air in the system somewhere. Oil leaks in the HPOP system will usually cause problems with a hot start, not a cold start. It could always be a sticky injector. Usually 200,000 miles is about all you can get on a set of HPOP injectors. Hope that helps.

[@recoilrob324]

Yes....they need the glow plugs to start well in cold weather, but once you've replaced them there is one additional test to do: Injector Buzz Test. You need a scanner to do this but when cold all 8 injectors will 'buzz' as the computer rapidly activates the solenoids. The buzz test runs all of them for a second then by firing order each one so you can hear which one/s don't buzz if they're bad. You can also tell by sound if some buzz strongly or weakly. The reason they buzz is the armature that's lifted by the solenoid magnet strikes makes a click each time it's activated. The big thing with high mileage that happens is the clearance under the armature plate to the injector body is only .004" and the valve seat that the armature lifts to inject is angled at 45 degrees and as it wears the armature drops which decreases the clearance gap. The oil in the gap gets stickier as the clearance decreases which makes the armature harder to break free...especially when the oil is cold and thick. Plus the solenoid magnet gets weaker as the distance to the armature increases....so when the oil is thick you get no injection and no start. You don't need to buy rebuilt injectors....you can measure the armature gap and shim them to correct specs and this will often restore performance as well as cold starting. Costs about $70 for the special tools and shims to do the job which is a hell of a lot cheaper than buying new injectors.